So there is no problem with “inline & defer” as such (from a narrow AO perspective), but with the generated critical css. The fact you still have render blocking is because part of the elements in the above-the-fold content are rendered (and/ or styled) by JavaScript, which is invisible to most (all?) Critical CSS generating services. If you compare the 2 screenshots under “prioritize visible content” you’ll see some differences, it’s those differences that will require (manual) tweaks to your critical CSS. If you tried the premium criticalcss.com service to generate the critical CSS, you could always ask them for assistance to fix this.
To be clear; as can be seen in this test your critical CSS is being used to render the page even before the normal CSS is loaded (rendering starts at 1.5s, the normal CSS is only downloaded at 1.85s.
If I were you I would now first and foremost focus on “reduce server response time” (the test I linked to shows a 0,8 time to first byte for your HTML). It looks like your hoster has a caching layer, but that is (probably) not working due to one or more plugins using PHP-sessions (which is a killer for most caching solutions and is an anti-pattern in WordPress development).
Hope this helps,
frank